Cell adhesion characteristics of a monocytic cell line derived from rainbow trout, Oncorhynchus mykiss

In experiments investigating the adhesive properties of the rainbow trout splenic monocyte-like cell line RTS11 it was found that the cells bound with low affinity to plates coated with bovine serum albumin (BSA) but that phorbol ester-induced activation/differentiation greatly increased adhesion to BSA. Similarly, pre-exposure to 500 μM MnCl2 at time of plating, increased RTS11 adhesion to BSA coated plates, in agreement with the reported ability of divalent cations such as Mn2+ to activate integrins. Integrins are a diverse family of heterodimeric cell surface glycoproteins that have been shown to mediate cell–cell and cell–extracellular matrix adhesion. Transcripts of the β2-integrin CD18 were detected by PCR in RTS11 but not in RTG-2 cells, a fibroblastic lineage derived from rainbow trout gonads. These results suggest that differentiated RTS11 express molecules related to members of the β2-integrin subfamily such as the macrophage lineage marker Mac-1 (CD11b/CD18) and/or p150,95 (CD11c/CD18) and possibly as well α4β1 of the β1-integrin subfamily.